Add MongoDB Atlas Vector store

 - Add VectorSearchAggregation used to actually preform the search
   on a given collection with embeddings.
 - add MongoDBVectorStore
 - Add MongoDBVectorStoreIT.  Integration test runs fine given...
   - You have a mongo atlas cluster to connect to (local or remote)
   - You have the search index "spring_ai_vector_search" setup correctly
   - Need to explore getting around this
   - Need to filter results using threshold
 - Add postfilter for threshold values - While a post filter is not ideal,
   it gets the job done. The mongo team seems to be working on having
   it availible as a prefilter option, in which this implementation
   can be updated to use later.
 - implement filtering threshold
 - fix a few sonar issues
 - formatting
 - use higher default num_candidates
 - use builder for configuration
 - add documentation and some refactor
 - use consistent property in integration test
 - finish implementing filter support
 - add documentation to filter converter
 - add vector search index auto creation

 - Add to BOM.
 - Fix version to 1.0.0-SN.
 - Move expresion converter from core to models/mongodb.
 - Fix style and license headers

Author: Kirbstomper

pom.xml

@@ -60,6 +60,7 @@
 		<module>spring-ai-spring-boot-starters/spring-ai-starter-bedrock-ai</module>
 		<module>spring-ai-spring-boot-starters/spring-ai-starter-mistral-ai</module>
 		<module>spring-ai-retry</module>
+		<module>vector-stores/spring-ai-mongodb-atlas-store</module>
 	</modules>
 
 	<organization>

spring-ai-bom/pom.xml

@@ -174,6 +174,12 @@
                 <version>${project.version}</version>
             </dependency>
 
+            <dependency>
+                <groupId>org.springframework.ai</groupId>
+                <artifactId>spring-ai-mongodb-atlas-store</artifactId>
+                <version>${project.version}</version>
+            </dependency>
+
             <!-- Utilities -->
             <dependency>
                 <groupId>org.springframework.ai</groupId>

vector-stores/spring-ai-mongodb-atlas-store/pom.xml

@@ -0,0 +1,59 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.springframework.ai</groupId>
+        <artifactId>spring-ai</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+    <artifactId>spring-ai-mongodb-atlas-store</artifactId>
+    <packaging>jar</packaging>
+    <name>Spring AI MongoDB Atlas Vector Store</name>
+    <description>Spring AI MongoDB Atlas Vector Store</description>
+    <url>https://github.com/spring-projects-experimental/spring-ai</url>
+
+    <scm>
+        <url>https://github.com/spring-projects/spring-ai</url>
+        <connection>git://github.com/spring-projects/spring-ai.git</connection>
+        <developerConnection>git@github.com:spring-projects/spring-ai.git</developerConnection>
+    </scm>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.ai</groupId>
+            <artifactId>spring-ai-core</artifactId>
+            <version>${parent.version}</version>
+        </dependency>
+        <!-- MongoDB -->
+        <dependency>
+            <groupId>org.springframework.data</groupId>
+            <artifactId>spring-data-mongodb</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.mongodb</groupId>
+            <artifactId>mongodb-driver-sync</artifactId>
+        </dependency>
+
+        <!-- TESTING -->
+        <dependency>
+            <groupId>org.springframework.ai</groupId>
+            <artifactId>spring-ai-openai-spring-boot-starter</artifactId>
+            <version>${parent.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

vector-stores/spring-ai-mongodb-atlas-store/src/main/java/org/springframework/ai/vectorstore/MongoDBAtlasFilterExpressionConverter.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2023 - 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ai.vectorstore;
+
+import org.springframework.ai.vectorstore.filter.Filter;
+import org.springframework.ai.vectorstore.filter.converter.AbstractFilterExpressionConverter;
+
+import static org.springframework.ai.vectorstore.filter.Filter.ExpressionType.AND;
+import static org.springframework.ai.vectorstore.filter.Filter.ExpressionType.OR;
+
+/**
+ * Converts {@link Filter.Expression} into MongDB Atlas metadata filter expression format.
+ * (https://www.mongodb.com/docs/atlas/atlas-vector-search/vector-search-stage/#std-label-vectorSearch-agg-pipeline-filter)
+ *
+ * @author Chris Smith
+ * @since 1.0.0
+ */
+public class MongoDBAtlasFilterExpressionConverter extends AbstractFilterExpressionConverter {
+
+	@Override
+	protected void doExpression(Filter.Expression expression, StringBuilder context) {
+		// Handling AND/OR
+		if (AND.equals(expression.type()) || OR.equals(expression.type())) {
+			doCompoundExpressionType(expression, context);
+		}
+		else {
+			doSingleExpressionType(expression, context);
+		}
+	}
+
+	private void doCompoundExpressionType(Filter.Expression expression, StringBuilder context) {
+		context.append("{");
+		context.append(getOperationSymbol(expression));
+		context.append(":[");
+		this.convertOperand(expression.left(), context);
+		context.append(",");
+		this.convertOperand(expression.right(), context);
+		context.append("]}");
+	}
+
+	private void doSingleExpressionType(Filter.Expression expression, StringBuilder context) {
+		context.append("{");
+		this.convertOperand(expression.left(), context);
+		context.append(":{");
+		context.append(getOperationSymbol(expression));
+		context.append(":");
+		this.convertOperand(expression.right(), context);
+		context.append("}}");
+	}
+
+	private String getOperationSymbol(Filter.Expression exp) {
+		switch (exp.type()) {
+			case AND:
+				return "$and";
+			case OR:
+				return "$or";
+			case EQ:
+				return "$eq";
+			case NE:
+				return "$ne";
+			case LT:
+				return "$lt";
+			case LTE:
+				return "$lte";
+			case GT:
+				return "$gt";
+			case GTE:
+				return "$gte";
+			case IN:
+				return "$in";
+			case NIN:
+				return "$nin";
+			default:
+				throw new RuntimeException("Not supported expression type:" + exp.type());
+		}
+	}
+
+	@Override
+	protected void doKey(Filter.Key filterKey, StringBuilder context) {
+		var identifier = (hasOuterQuotes(filterKey.key())) ? removeOuterQuotes(filterKey.key()) : filterKey.key();
+		context.append("\"metadata." + identifier + "\"");
+	}
+
+}